code_poly: Build polynomial predictor variables

In jgeller112/gazer: Tools for Processing Eye Tracking Data

Description

Takes a data frame, name of predictor variable, and polynomial order. Creates polynomial-transformed predictor variables, adds them to the data frame and returns the result. Original data frame is unchanged, remember to assign the result.

Usage

code_poly(df = NULL, predictor = NULL, poly.order = NULL,
  orthogonal = TRUE, draw.poly = TRUE)

Arguments

df	data frame, should not contain any variables called "predictor"
predictor	string name of predictor variable
poly.order	integer order of polynomial to be created
orthogonal	logical value indicating whether polynomial should be orthogonal (default) or natural (aka raw)
draw.poly	logical value indicating whether to create a graph showing tranformed polynomial predictor values, defaults to TRUE

Value

Returns a data frame containing the original data and at least two new columns: "predictor".Index, and a column for each order of the polynomial-transformed predictor

Examples

WordLearnEx.gca <- code_poly(df=WordLearnEx, predictor="Block", poly.order=2)
Az.gca <- code_poly(df=Az, predictor="Time", poly.order=2, orthogonal=FALSE)

jgeller112/gazer documentation built on Jan. 13, 2020, 1:04 p.m.